" In vivo effect of non thermal millimeter electromagnetic waves (MEMWs) with 50.3 GHz (which coincides with resonant frequencies of oscillations of water molecular structures) and 48.3 GHz (which does not coincide with resonant frequencies) frequencies on DNA primary and secondary structures of liver of healthy rats as well as Sarcoma-45 tumor carrying rats has been studied. It was shown, that under the effect of MEMWs with 50.3 GHz during 60 min, the content of 5-methylcitosine, the melting parameters of DNA of Sarcoma-45 tumors changed and approached to respective values of DNA extracted from the liver of healthy animals."